Data and Transaction Flow in Blockchain BDC Practice Questions (Page 5)

Questions 21–25

1. 21application · medium

   A developer is building a custom blockchain and needs to design a transaction format that allows a user to spend multiple unspent outputs from different addresses in a single transaction. Which transaction component is essential to support this?

   • AA list of inputs, each referencing a previous transaction output and providing a signature
   • BA special flag indicating that the transaction is a multi-input transaction
   • CA single signature that covers all inputs
   • DA single output that combines the total value of all inputs
   Reveal Solution Discussion Select an answer first
2. 22expert · hard

   A developer is explaining to a client why a transaction on a Proof-of-Stake blockchain is considered final after a certain number of blocks. Which property of PoS contributes to this finality?

   • AThe network uses a longer epoch duration to reduce block production frequency.
   • BValidators are economically penalized for attempting to reorganize the chain.
   • CThe block's Merkle root is fixed and cannot be changed.
   • DValidators are chosen randomly, making it impossible to predict the next block producer.
   Reveal Solution Discussion Select an answer first
4. 23foundation · easy

   What is the first step a miner takes when creating a new block?

   • AVerifying the proof-of-work of the previous block
   • BSelecting a set of valid transactions from the mempool
   • CBroadcasting the block to the network
   • DCalculating the Merkle root of the previous block
   Reveal Solution Discussion Select an answer first
5. 24expert · hard

   A miner is assembling a block and has a mempool with the following transactions: TxA (fee 0.001 BTC, size 100 bytes), TxB (fee 0.002 BTC, size 300 bytes), TxC (fee 0.003 BTC, size 500 bytes). The block size limit is 600 bytes. Which transactions should the miner include to maximize total fees?

   • ATxB and TxC
   • BTxC only
   • CTxA and TxB
   • DTxA and TxC
   Reveal Solution Discussion Select an answer first
6. 25foundation · easy

   How does blockchain immutability primarily protect the integrity of recorded transactions?

   • ABy storing all data in a centralized database with backup copies
   • BBy encrypting all transaction data so only authorized parties can read it
   • CBy using cryptographic hashes that link each block to the previous one, making tampering evident
   • DBy requiring all transactions to be approved by a central authority
   Reveal Solution Discussion Select an answer first